Microsoft SharePoint SPFieldMultiLineText Cross-Site Scripting Vulnerability
Vulnerability Details
This vulnerability allows remote attackers to execute web requests with a target user's privileges on affected installations of Microsoft SharePoint. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the SPFieldMultiLineText class. The issue results from the lack of proper validation of user-supplied data, which can lead to the injection of an arbitrary script. An attacker can leverage this vulnerability to execute script in the context of a target user.
Additional Details
Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-55126
Disclosure Timeline
- 2026-05-07 - Vulnerability reported to vendor
- 2026-07-15 - Coordinated public release of advisory
- 2026-07-15 - Advisory Updated
Credit
Vladislav Berghici of TrendAI Research
